late 14c., "gaping void," from Old French chaos (14c.) or directly from Latin chaos, from Greek khaos "abyss, that which gapes wide open, is vast and empty," from *khnwos, from PIE root *gheu- "to gape, yawn" (cf. Greek khaino "I yawn," Old English ginian, Old Norse ginnunga-gap; see yawn (v.)).

Meaning "utter confusion" (c.1600) is extended from theological use of chaos for "the void at the beginning of creation" in Vulgate version of Genesis (1530s in English). The Greek for "disorder" was tarakhe, however the use of chaos here was rooted in Hesiod ("Theogony"), who describes khaos as the primeval emptiness of the Universe, begetter of Erebus and Nyx ("Night"), and in Ovid ("Metamorphoses"), who opposes Khaos to Kosmos, "the ordered Universe." Meaning "orderless confusion" in human affairs is from c.1600. Chaos theory in the modern mathematical sense is attested from c.1977.

(kā'ŏs') The behavior of systems that follow deterministic laws but appear random and unpredictable. Chaotic systems very are sensitive to initial conditions; small changes in those conditions can lead to quite different outcomes. One example of chaotic behavior is the flow of air in conditions of turbulence. See more at fractal.

chaos definition

A new branch of science that deals with systems whose evolution depends very sensitively upon the initial conditions. Turbulent flows of fluids (such as white water in a river) and the prediction of the weather are two areas where chaos theory has been applied with some success.

mathematics A property of some non-linear dynamic systems which exhibit sensitive dependence on initial conditions. This means that there are initial states which evolve within some finite time to states whose separation in one or more dimensions of state space depends, in an average sense, exponentially on their initial separation. Such systems may still be completely deterministic in that any future state of the system depends only on the initial conditions and the equations describing the change of the system with time. It may, however, require arbitrarily high precision to actually calculate a future state to within some finite precision. ["On defining chaos", R. Glynn Holt rgholt@voyager.jpl.nasa.gov and D. Lynn Holt lholt@seraph1.sewanee.edu. (ftp://mrcnext.cso.uiuc.edu/pub/etext/ippe/preprints/Phil_of_Science/Holt_and_Holt.On_Defining_Chaos)] Fixed precision floating-point arithmetic, as used by most computers, may actually introduce chaotic dependence on initial conditions due to the accumulation of rounding errors (which constitutes a non-linear system). (1995-02-07)